U.S. patent application number 11/921067 was filed with the patent office on 2009-12-24 for apparatus for communicating with a memory tag and use of the same.
This patent application is currently assigned to IVF LIMITED. Invention is credited to David Charles Lansdowne.
Application Number | 20090318751 11/921067 |
Document ID | / |
Family ID | 36660741 |
Filed Date | 2009-12-24 |
United States Patent
Application |
20090318751 |
Kind Code |
A1 |
Lansdowne; David Charles |
December 24, 2009 |
Apparatus for Communicating with a Memory Tag and Use of the
Same
Abstract
A work station comprises a surface (11) for supporting a sample
(12); a temperature controller for controlling the temperature of
the surface; and apparatus (16) for communicating with a memory tag
via a wireless electromagnetic link. The apparatus is located
beneath the surface in order to communicate with a memory tag on or
over the surface. A soft magnetic member is provided. The
temperature controller comprises a chamber containing a liquid; a
pump for pumping the liquid into the chamber; an inlet channel
between the pump and the chamber; and an inlet weir extending
across the inlet channel so as to impede the flow of liquid through
the inlet channel into the main chamber. The work station is of
particular use in the monitoring of samples being used in in-vitro
fertilisation procedures.
Inventors: |
Lansdowne; David Charles;
(Cornwall, GB) |
Correspondence
Address: |
Kimberly A. Chasteen
PO Box 1243
Yorktown
VA
23692
US
|
Assignee: |
IVF LIMITED
Cornwall
GB
|
Family ID: |
36660741 |
Appl. No.: |
11/921067 |
Filed: |
May 23, 2006 |
PCT Filed: |
May 23, 2006 |
PCT NO: |
PCT/GB2006/001898 |
371 Date: |
August 27, 2009 |
Current U.S.
Class: |
600/35 ; 235/439;
235/449; 235/492 |
Current CPC
Class: |
H01Q 7/00 20130101; G01N
2035/00782 20130101; B01L 2300/185 20130101; G01N 35/00732
20130101; B01L 9/02 20130101; B01L 7/04 20130101; B01L 2300/022
20130101; B01L 2300/023 20130101; G06K 7/10326 20130101; H01Q 1/22
20130101; B01L 2400/0487 20130101; B01L 7/00 20130101; G06K 7/10366
20130101; B01L 3/545 20130101; B01L 2300/021 20130101 |
Class at
Publication: |
600/35 ; 235/449;
235/492; 235/439 |
International
Class: |
A61B 17/43 20060101
A61B017/43; G06K 7/08 20060101 G06K007/08; G06K 19/06 20060101
G06K019/06; G06K 7/00 20060101 G06K007/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 24, 2005 |
EP |
05076393.7 |
May 24, 2005 |
GB |
PCT/GB2005/002048 |
Claims
1. A work station comprising; a plate for supporting a sample; a
temperature controller for controlling the temperature of the
plate; and an antenna for communicating with a memory tag via a
wireless electromagnetic link, the antenna being located beneath
the plate in order to communicate with a memory tag on or over the
plate; wherein the plate is thermally conducting from one face to
the other, and the temperature controller is in thermal contact
with a lower face of the plate.
2. A work station according to claim 1, in which the plate
comprises an electrically-insulating or resistive plate.
3. A work station according to claim 1, in which the plate
comprises a glass plate, and the temperature controller comprises
an electrically-conducting heating layer provided as a coating on
the lower face of the plate.
4. A work station according to claim 3, wherein the
electrically-conducting heating layer comprises a layer of indium
tin oxide.
5. A work station according to claim 1, wherein the
temperature-controller comprises a liquid.
6. A work station according to claim 5, further comprising: a
chamber containing the liquid; a pump for pumping the liquid into
the chamber; an inlet channel between the pump and the chamber; and
an inlet weir extending across the inlet channel so as to impede
the flow of liquid through the inlet channel into the main
chamber.
7. A work station according to claim 6 wherein the inlet weir is
elongate in a direction transverse to a direction of flow of water
across the inlet weir.
8. A work station according to claim 6 further comprising one or
more additional inlet channels between the pump and the chamber;
each additional inlet channel having an inlet weir extending across
the additional inlet channel so as to impede the flow of liquid
through the additional inlet channel into the main chamber.
9. A work station according to claim 6, further comprising an
outlet channel; and an outlet weir extending across the outlet
channel so as to impede the flow of liquid from the main chamber
into the outlet channel.
10. A work station according to claim 9 wherein the outlet weir is
elongate in a direction transverse to a direction of flow of water
across the outlet weir.
11. A work station according to claim 6 further comprising one or
more additional outlet channels; each additional outlet channel
having an outlet weir extending across the additional outlet
channel so as to impede the flow of liquid from the main chamber
into the additional outlet channel.
12. A work station comprising: a surface for supporting a sample; a
temperature controller for controlling the temperature of the
surface; and an antenna for communicating with a memory tag via a
wireless electromagnetic link, the antenna being located beneath
the surface in order to communicate with a memory tag on or over
the surface; and a soft magnetic member.
13. A work station according to claim 12 wherein the temperature
controller comprises a heater.
14. An apparatus for communicating with a memory tag via a wireless
electromagnetic link, the apparatus comprising: an antenna coil
which has an inner edge defining an antenna axis and a coil
interior; and a soft magnetic member which, when viewed along the
antenna axis, overlaps with some, but not all, of the coil
interior.
15. Apparatus according to claim 14 further comprising two or more
soft magnetic members, each of which, when viewed along the antenna
axis, overlaps with some, but not all, of the coil interior.
16. An apparatus according to claim 14 further comprising a
shielding soft magnetic member which, when viewed along the antenna
axis, overlaps with the coil.
17. An apparatus for providing a temperature-controlled surface,
the apparatus comprising: a thermally conducting plate; a chamber
containing a liquid in thermal contact with the plate; a pump for
pumping the liquid into the chamber; an inlet channel between the
pump and the chamber; and an inlet weir extending across the inlet
channel so as to impede the flow of liquid through the inlet
channel into the chamber.
18. (canceled)
19. (canceled)
20. A method for coding and identification of biological samples
for in-vitro fertilisation, the method comprising the steps of:
applying to receptacles intended for unfertilised eggs and sperm,
respectively, an identification code characteristic of a patient;
placing unfertilised eggs and sperm, respectively in the
receptacles; storing, transporting and admixing the respective
samples in receptacles which each carry the same code; and
implanting the resulting embryo in the patient.
21. The method according to claim 20, wherein the identification
codes are computer-readable.
22. The method according to claim 20, wherein the identification
code is based on RFID technology, sample vessels being codified by
the application of an RFID tag.
23. The method according to claim 21, wherein information relating
to the receptacles and samples stored therein is maintained in a
database.
24. The method according to claim 23, wherein the database is
controlled by software which includes an anti-collision protocol to
discriminate between data received from a plurality of vessels
having different identification codes attached thereto.
25. The method according to claim 22, wherein one or more steps of
the method are carried out on a laboratory bench beneath which is
located an antenna for transmission of activation radiation and
receiving signals emitted by the RFID tag.
26. An apparatus for identification of biological samples for
in-vitro fertilisation, the apparatus comprising: storage vessels
associated with an identification code; and means to read the code
and transmit information relating to the samples to a database.
27. A work station providing a warmed surface for supporting
biological samples and comprising RFID tag reading means located
beneath the surface for reading RFID tags on or over the surface,
wherein the station is structured such that warming of the surface
is achieved without preventing reading by the reading means of an
RFID tag associated with an item placed on the surface.
28. A work station comprising a work area defined by an
electrically-insulating or resistive plate beneath which in use is
located an antenna for transmitting electromagnetic signals to
sample receptacles placed on the work area and receiving
identification signals therefrom, in which the plate is thermally
conducting from one face to the other, the lower surface being in
thermal contact with a temperature-controlled heating medium.
29. A work station according to claim 28, wherein the plate
comprises glass coated on its lower surface with an
electrically-conducting heating layer as the heating medium.
30. A work station according to claim 28, wherein the plate
comprises upper and lower plate elements defining a cavity
therebetween for containing a liquid heating medium.
31. A work station according to claim 30, wherein the heating
medium comprises water at a thermostatically-controlled
temperature.
32. (canceled)
33. (canceled)
Description
[0001] A first aspect of the invention relates to apparatus for
communicating with a memory tag (such as an RFID tag) via a
wireless electromagnetic link. The apparatus is typically (although
not exclusively) for the identification of temperature-controlled
samples, such as biological samples for use in in-vitro
fertilisation processes. A second aspect of the invention provides
apparatus for providing a temperature-controlled surface.
[0002] In-vitro fertilisation is a process which is intended to
enable a woman, apparently unable to conceive naturally, to gestate
and give birth by implantation, in the womb, of an
externally-fertilised egg. During the process, unfertilised eggs
are collected from the patient's ovaries and admixed with sperm
from the woman's partner for fertilisation purposes, the fertilised
egg then being re-implanted in the womb for gestation. Clearly, it
is important for the procedure to be administered under a rigorous
and carefully-controlled protocol to ensure that the eggs are
fertilised with sperm from the intended partner; various instances
have been reported in the media concerning unintended and highly
distressing errors which become apparent following birth. To this
end, the Human Fertilisation and Embryology Authority operates a
so-called "locked in process", in which the procedure is witnessed
at every stage by a person additional to the operative to ensure,
as far as possible, that mistakes such as have been made in the
past are not repeated in the future. The procedure is consequently
expensive to operate and administer and, in any event, the
possibility of human error cannot entirely be eliminated.
[0003] Accordingly, there is a need to provide a procedure and
associated apparatus which enables samples to be coded and
identified, especially for use in in-vitro fertilisation
procedures, in a way which falls within the requirements of the
regulatory authorities, in the UK this being the Human
Fertilisation and Embryology Authority.
[0004] In particular, there is a need to provide an apparatus that
gives the person conducting the in-vitro fertilisation procedures a
secure zone, such as a sterile cabinet or working area. In this
respect, the term `secure zone` is to mean a space in which tagged
or labeled items entering or leaving any part of the space are
identified and logged.
[0005] EP 1 484 816 discloses an antenna for reader/writer and an
apparatus incorporating the antenna. The apparatus relies upon RFID
that is operable even when in contact with a conductive surface.
The apparatus comprises an antenna coil disposed on a soft magnetic
member, which in turn is in contact with a metal surface, such as a
casing. The apparatus of EP 1 484 816, while operable as a
reader/writer, has only a low read range, that is objects bearing
an RFID tag or label must be in very close proximity to the
antenna. In the handling of in-vitro fertilisation procedures, it
is necessary to operate within a space, such as a sterile cabinet
or the like. It is not feasible or practical for all the labeled
objects to be in close proximity to the antenna. Accordingly, the
system of EP 1 484 816 does not address the needs of the in-vitro
fertilisation procedures.
[0006] US 2002/0068358 discloses an in-vitro embryo culture device.
The device serves as an incubator for a single embryo. The device
incorporates a heater, to regulate the temperature of an embryo
contained within the device. A base assembly is provided, which
allows the status and condition of an embryo to be determined and
monitored, when the device is placed on the base assembly. This
document discloses nothing which assists with providing a secure
zone for in-vitro fertilisation procedures, as hereinbefore
described.
[0007] US 2005/0007296 discloses an antenna coil and an RFID-use
tag incorporating the antenna. The tag is provided with the antenna
in the form of a helical coil. As with EP 1 484 816, the antenna
coil is operable only at very short distances, resulting in the
device having a very low read range. Again, this device is not
suitable to provide a secure zone for use in conducting in-vitro
fertilisation procedures, as discussed hereinbefore.
[0008] Accordingly, there remains a need for a method and system
for providing a secure zone for the accurate monitoring of tagged
or labeled samples, in particular biological samples, during
procedures for handling the samples, such as in-vitro fertilisation
procedures. It would also be very useful if the secure zone could
include means for controlling the ambient or working temperature
within the zone without such means interfering with the accurate
monitoring of the tagged or labeled samples.
[0009] In a first aspect, the present invention provides a work
station comprising a surface for supporting a sample; a temperature
controller for controlling the temperature of the surface; and an
antenna for communicating with a memory tag via a wireless
electromagnetic link, the antenna being located beneath the surface
in order to communicate with a memory tag on or over the surface;
and a soft magnetic member.
[0010] An apparatus is also provided by the present invention, the
apparatus being for communicating with a memory tag via a wireless
electromagnetic link, and comprising an antenna coil which has an
inner edge defining an antenna axis and a coil interior; and a soft
magnetic member which, when viewed along the antenna axis, overlaps
with some, but not all, of the coil interior.
[0011] The work station and apparatus provide a secure zone for
conducting procedures using tagged or labeled items, such as
in-vitro fertilisation procedures, whereby such items moved into
and out of the region surrounding the work station or apparatus are
detected, without the need for the operator to bring each item into
close proximity to the antenna.
[0012] In a further aspect, the present invention provides work
station comprising a plate for supporting a sample; a temperature
controller for controlling the temperature of the plate; and an
antenna for communicating with a memory tag via a wireless
electromagnetic link, the antenna being located beneath the plate
in order to communicate with a memory tag on or over the plate;
wherein the plate is thermally conducting from one face to the
other, and the temperature controller is in thermal contact with a
lower face of the plate.
[0013] An apparatus for providing a temperature-controlled surface
is also provided by the present invention, the apparatus comprising
a thermally conducting plate; a chamber containing a liquid in
thermal contact with the plate; a pump for pumping the liquid into
the chamber; an inlet channel between the pump and the chamber; and
an inlet weir extending across the inlet channel so as to impede
the flow of liquid through the inlet channel into the chamber.
[0014] Preferred and further features of the work station and
apparatus of the aforementioned aspects of the present invention
are recited in the accompanying claims.
[0015] In still a further aspect, the present invention provides a
method for coding and identification of biological samples for
in-vitro fertilisation, the method comprising the steps of
identifying receptacles intended for unfertilised eggs and sperm,
respectively, with an identification code characteristic of the
patient; placing unfertilised eggs and sperm, respectively, in the
receptacles; storing, transporting and admixing the respective
samples in receptacles which each carry the same code; and
implanting the resulting embryo in the patient. Preferably, the
identification codes are computer-readable, for example via a bench
top reader, and information relating to the vessels and the samples
stored therein is maintained in a database which tracks the vessels
and samples and can provide information concerning their location
at any given time.
[0016] Preferably, the identification code is based on RFID
technology, in which sample vessels are identified by the
application of write-on or printable adhesive labels having an RFID
tag permanently attached thereto or incorporated therein,
identification being by means of activation by radiation in the
form of radio frequency waves, the tag emitting identification
signals which can be received by the reader and stored in the
database. In alternative embodiments, ID tags utilising
electromagnetic frequencies other than radio frequencies, such as
microwave frequencies may be used. The database may be controlled
by software which includes an anti-collision protocol to
discriminate between data received from a plurality of vessels
having different identification codes attached thereto.
[0017] In another aspect, the invention provides apparatus for
identification of biological samples for in-vitro fertilisation,
the apparatus comprising storage vessels associated with an
identification code; and means to read the code and transmit
information relating to the samples to a database.
[0018] In this specification, the term "vessels" is intended to
cover vessels for use at any stage of the overall in-vitro
fertilisation procedure between initial collection of the egg and
sperm samples, storage thereof, admixing thereof for fertilisation
purposes and transmission of the embryo to the patient for
implantation. Also in this specification, the term "patient" is to
be understood, as the context requires, as applying either to the
woman or to the male partner.
[0019] In operation of the process and as reassurance for the
patient, the patient can observe and verify that the initial
samples are placed in vessels which correctly identifies the
patient and that the embryo is also thus identified.
[0020] The method of the invention is preferably carried out on a
laboratory bench, beneath which is located an antenna for
transmission of activation radiation and receiving signals emitted
by the RFID tag. It is necessary, in order for the samples to
remain viable, for the bench surface to be heated to a controlled
temperature, preferably in the range of from 37 to 42.degree. C.
When handling or manipulating samples using conventional
techniques, bench surfaces are typically made from stainless steel.
Heating thereof is by means of pipes disposed under and spaced from
the bench top and through which hot water is circulated. A
heat-conductive plate, typically of aluminium or an aluminium
alloy, is provided between the pipes and the surface material to
equilibrate the temperature differences between the pipes and their
surroundings and result in a substantially uniform surface
temperature. However, with the method of the present invention,
signals between the antenna and samples will not transmit through a
metal bench top, nor will they communicate with an RFID tag in
close proximity, typically 1 mm or less, to a metal surface. It is
therefore necessary to utilise an electrically non-conducting
material for the bench top, but this mitigates against the use of
temperature control measures which rely on thermal conduction from
beneath the surface.
[0021] The reading means comprises an antenna and a reader for
reading RFID tags. The antenna forms part of an electrical circuit
that is configured to optimise the reading of RFID tags on or over
the surface. The circuit includes a transformer for providing power
to the antenna and also an adjustable capacitor and an adjustable
reservoir. The transformer is configured to minimise any impedance
mismatch between the reader and the antenna to improve the prospect
of an RFID tag being readable on or over the entire surface. The
adjustable capacitor is set to tune to resonance the coupling
between the antenna and the RFID tag over the surface. The
adjustable resistor is set to dampen the magnetic field that the
antenna produces over the surface so that RFID tags placed over the
surface are not `swamped`.
[0022] According to another aspect, the present invention provides
a work station providing a warmed surface for supporting biological
samples and comprising RFID tag reading means located beneath the
surface for reading RFID tags on or over the surface, wherein the
station is structured such that warming of the surface is achieved
without preventing reading by the reading means of an RFID tag
associated with an item placed on the surface.
[0023] In one embodiment, the work station comprises a work area
defined by an electrically-insulating or resistive plate beneath
which, in use, is located an antenna for transmitting
electromagnetic signals to sample receptacles placed on the work
area and receiving identification signals therefrom, in which the
plate is thermally conducting from one face to the other, the lower
surface being in thermal contact with a temperature-controlled
heating medium. The work area may be set in a workbench, which may
be made, for example, from stainless steel, the work area providing
a secure zone, that is a discrete working zone for the antenna and
manipulation operations carried out on the upper surface.
[0024] The plate may comprise glass coated on its lower surface
with an electrically-conducting heating layer, such as indium tin
oxide, as the heating medium. Alternatively, the plate may comprise
upper and lower plate elements defining a cavity between them for
containing a liquid heating medium, for example water, at a
thermostatically-controlled temperature. Preferably, the water is
pumped and recirculated through the cavity at a sufficiently high
flowrate to minimise the temperature drop across the work area.
Preferably, the flow of the liquid heating medium is laminar.
[0025] Embodiments of invention will now be described by way of
example with reference to the accompanying drawings, in which:
[0026] FIG. 1 is a diagrammatic view of a work station utilising
one form of heating means;
[0027] FIG. 2 is a diagrammatic view of another embodiment using
another form of heating means;
[0028] FIG. 3 is an isometric view of the upper side of a table-top
work station;
[0029] FIG. 4 shows upper side of the table-top work station with
the housings removed;
[0030] FIG. 5 is an isometric view of the underside of the
table-top work station;
[0031] FIG. 6 shows the underside of the table-top work station
with the lower plate removed;
[0032] FIG. 7 shows the underside of the upper plate only;
[0033] FIG. 8 shows the underside of the lower plate only;
[0034] FIGS. 9-11 show the underside of the upper plate with
various different configurations of soft magnetic strips; and
[0035] FIG. 12 is a cross-sectional side view of an embodiment of
the workstation of the present invention in use.
[0036] With reference firstly to FIG. 1, the apparatus consists
essentially of a stainless steel workbench surface (10) having an
insert defining a work area and consisting of a toughened glass
plate (11). A petri dish (12) having an RFID tag (13) attached to
the under surface thereof is placed on the work station. The glass
plate (11) carries a lower coating or deposit (14) formed from
indium tin oxide, the layer being electrically connected to a power
supply to provide an even heating current. An antenna (16) is
disposed below the work station and connected to test equipment
(17).
[0037] In use, the antenna coil transmits activation signals to the
RFID tag (13) which itself transmits identification signals back to
the antenna, the signals being processed in the test equipment
(17). The power supply (15) supplies energy to the indium tin oxide
layer (14) for heating purposes; the heat generated is transmitted
through the plate (11) to maintain the upper surface of the plate
at the desired temperature.
[0038] With reference to FIG. 2, the work station consists
essentially of upper and lower Corian (Registered Trade Mark)
plates (21, 22) set into a workbench as shown in FIG. 1. The plates
are spaced apart to define a gap (23) through which
temperature-controlled water is passed in laminar flow to maintain
the upper surface of the work station at the desired temperature.
The work station is provided with an antenna and test equipment as
described and illustrated with reference to FIG. 1.
[0039] Referring to FIGS. 3-8, a table-top workstation 30 comprises
a Corian.TM. upper plate 31, a pair of housings 32, 33 which are
mounted to the upper plate 31, and a Corian.TM. lower plate 34.
[0040] FIG. 7 shows the underside of the device with the lower
plate 34 removed. As shown in FIG. 7, the underside of the upper
plate 31 has a flange 40 running around its outer periphery, and
dividers 41, 42. The flange 40 and dividers 41, 42 have holes (not
labeled) which receive screws (shown in FIG. 6) which screw the
lower plate 34 to the upper plate 31. A space 50 is provided
between the divider 41 and the flange 40, and a space 51 is
provided between the divider 42 and the divider 41.
[0041] The upper plate 31 has a hole 43 which receives a display
unit 44 and a transformer 45, which are mounted to the lower plate
34.
[0042] The upper plate 31 also has a hole 46 which receives a water
pump 47 and an Aluminium heater block 48, also mounted to the lower
plate 34. Wires (not shown) connect the pump 47 to the transformer
45, which provides power to the pump.
[0043] A sealing block 52 fits into the space 51, and has an inlet
which is connected to an outlet 53 of the pump by a pipe (not
shown). The sealing block 52 channels water from the pump via a
channel 54 to a water flow distribution block 55. The upper wall of
the channel 54 is formed by the upper plate 31, and the lower wall
of the channel 54 is formed by the lower plate 34 (not shown in
FIG. 6).
[0044] The flow distribution block comprises two L-shaped walls
which divide the flow into three inlet channels 56-58, and three
inlet weirs 59-61 which extend across the inlet channels 56-58. The
inlet weirs 59-61 have a height approximately 0.3 mm less than the
L-shaped walls, thus impeding the flow, but providing a 0.3 mm slit
through which water can flow out of the inlet channels 56-58 into a
main water chamber 62. The inlet channels 56-58 distribute the flow
uniformly across the width (front to back) of the chamber 62, and
the inlet weirs 59-61 ensure laminar flow across the width of the
outlets of the inlet channels 56-58.
[0045] The water flows across the main chamber 62 and exits via a
water collection block 63 which is identical to the flow
distribution block 55 and therefore will not be described in
detail. The water collection block 63 directs flow through an
outlet 64 into the heater block 48 which is connected in turn to an
inlet of the pump 47.
[0046] The flow rate is kept as high as possible to ensure that the
temperature drop between the flow distribution block 55 and the
water collection block 63 is as small as possible.
[0047] The lower and upper plates have circular holes 160, 161
respectively which receive respective glass windows 162, 163. A
slot 164 (shown in FIG. 3) receives a stereo-zoom microscope in
use. Light is projected upwardly through the glass windows 162, 163
into a vessel (such as a petri dish) placed on the glass window
163, enabling the microscope to view the sample.
[0048] A channel 70 (which forms a closed loop) is formed in the
underside of the upper plate, and receives an RFID antenna (not
shown) in use. The antenna comprises a single turn of adhesive
copper strip which is spray-coated with waterproof insulating
material. The ends of the copper strip pass through hole 51 where
they are connected to a small PCB-mounted tuning circuit 72. The
tuning circuit includes an impedance matching transformer;
adjustable series and parallel capacitances; and an adjustable
series resistance. The adjustable capacitances and resistances
enable the antenna to be tuned. A coaxial cable (not shown)
connects the tuning circuit to a coaxial output port 73 shown in
FIG. 4.
[0049] In the embodiment shown, the antenna is placed above the
water, but in an alternative embodiment (not shown) the antenna
coil may be placed below the water.
[0050] The underside of the lower plate 34 has a shallow recess 71
which receives a continuous sheet of self-adhesive soft magnetic
material (not shown), cut with a hole around the glass window. The
material may be any of the materials described in EP-A-1484816.
Preferably the material is a sheet of EMI suppression material,
Product Code PE73 or PE73, provided by FDK Corporation of Tokyo,
Japan. This product is chosen due to its high initial
permeability.
[0051] The sheet of soft magnetic material forms a shield which
decouples the antenna coil from any surrounding metal work. When
viewed along an antenna axis (transverse to FIGS. 9-11) the sheet
overlaps slightly with the coil in order to maximise the shielding
effect.
[0052] Strips of self-adhesive soft magnetic material are also
attached to the upper plate 31. The strips may be formed from the
same material as the shielding sheet mounted on the lower plate, or
from a different soft magnetic material. Various patterns may be
used, and examples are given in FIGS. 9-11. In each case, the
strips are approximately 100 mm long, 2 mm wide, and spaced apart
by 2 mm.
[0053] In the case of FIG. 9, the strips are arranged in parallel.
In the case of FIG. 10, the strips are arranged in parallel in a
"brickwork" pattern with successive lines of strips offset from
each other. In the case of FIG. 11, the strips radiate outwardly
from the glass windows 62, 63.
[0054] The antenna is indicated schematically at 65. The antenna 65
has an inner edge defining an antenna axis (transverse to FIG. 9)
and a coil interior 66. Each strip of soft magnetic material, when
viewed along the antenna axis as in the view of FIG. 9, overlaps
with some, but not all, of the coil interior 66. The same is true
for the strips in FIGS. 10 and 11. The magnetic field is is
circular (toroidal) around the coil 65. The intensity gets weaker
as the distance from the coil 65 increases. In order to obtain a
more even field across the coil interior, the strips of soft
magnetic material are spaced from the coil towards the centre of
the coil interior. Thus, in contrast to the continuous sheet housed
in the shallow recess 71 (which decouples the coil from surrounding
metal work), the strips perform a different function of
manipulating the magnetic field in the coil interior. The strips
may lie in the same plane as the coil, or may be positioned above
or below the plane of the coil.
[0055] The workstation 30 is shown in use in FIG. 12. A stainless
steel table 80 in a ventilated cabinet (not shown) has a recess in
its upper face which receives the base 81 of a microscope. The
microscope has a column 82 passing through the slot 64 in the rear
of the workstation 30, and head 83 positioned above the glass
window 63. A lamp 84 is positioned below the glass window 62 to
illuminate a sample in a vessel 85 carrying an RFID tag 86. The
workstation has a removable perforated wrist-rest 87 which is
positioned above a perforated region of the table 80. The
perforations permit the circulation of air in the ventilated
cabinet.
[0056] In an alternative embodiment (not shown), the embodiment of
FIG. 2 may incorporate a sheet of shielding soft magnetic material
with side walls which pass between the edge of the workbench 10 and
the glass plate 11, and a base which runs below the coil 16 (the
shield forming a U-shape in cross-section). Strips of soft magnetic
material (formed in one of the patterns shown in FIGS. 9-11 may be
adhered to the indium tin oxide layer 14.
[0057] In an alternative embodiment (not illustrated), the heating
arrangement shown in FIG. 6 (employing inlet and outlet weirs) may
be used to provide a temperature controlled surface in an
alternative application, without incorporating an RFID reader.
[0058] In further alternative embodiments, the water, or another
liquid medium, may be used to cool a sample instead of heating the
sample.
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